1. Technical Field
This application is related to vehicle radar systems, and, more particularly, to vehicle radar systems with blind spot detection.
2. Discussion of Related Art
Some automotive radar systems monitor the immediate surroundings of a host vehicle and can enable safety or comfort features such as blind spot detection and lateral collision avoidance. Blind spot detection radar sensors must cover a very wide area and must have the ability to classify the obstacles in the radar field of view. In particular, for example, the radar sensor must be able to distinguish a flat wall or guardrail from a stagnant vehicle at low speed, i.e., a vehicle travelling in the same direction and at approximately the same speed as the host vehicle.
Conventional vehicle blind spot detection/monitoring systems typically implement one broad radar transmit pattern and an array of receivers. The receiver beam is either steered or formed digitally. For example, in some systems, switchable relatively narrow beams scan the area of interest. This approach has the disadvantage of requiring multiple analog receiver circuits, which can be relatively high-cost. In other systems, a single broad transmit antenna is used for short range, and several, e.g., four, separate receivers are used to enable digital beam forming. These approaches to digital beam forming can also add substantially to the cost of the system.